Compress PDF Online Free
or drop PDF file here · Supports PDF · Up to 90MB
How Compress PDF Online Works
Fast, private in-browser document processing engineered with enterprise-grade accuracy.
Upload PDF
Upload the oversized PDF you want to shrink.
Optimize Content
Our engine optimizes embedded imagery, cleans streams, and compresses structural trees.
Download Smaller PDF
Compare initial and final file sizes, then download your optimized document.
Stream & Object Optimization
Cleans unreferenced font tables, obsolete metadata, and redundant object streams.
Text Remains Sharp
Vector outlines and text fonts are never rasterized or degraded.
Email-Ready Files
Easily brings bloated scans down below the typical 25MB email attachment limit.
Honest Compression
Actual size reduction depends on existing compression in the source file.
Frequently Asked Questions
Everything you need to know about formats, browser privacy, and file handling.
How do I reduce PDF file size for email attachments without losing readable quality?▼
Upload your document and choose our 'Recommended Compression' profile. It optimizes internal PDF fonts, strips duplicate metadata, and intelligently downsamples high-res images to 150 DPI—reducing file size by up to 70% while keeping text crystal clear.
What compression levels are available (Extreme, Recommended, Low compression)?▼
We offer three presets: 'Extreme Compression' (downsamples images to 72 DPI for smallest file size), 'Recommended Compression' (150 DPI, ideal for web and email sharing), and 'Low Compression' (300 DPI, preserves print quality while pruning redundant binary streams).
Why are some PDF files so large, and what gets optimized during compression?▼
PDF files bloat due to uncompressed 300+ DPI camera photos, redundant embedded fonts, unflattened graphic transparency layers, and embedded thumbnail caches. Compression streamlines these objects efficiently.
Does compressing a PDF make text blurry or unsearchable?▼
No. Text is stored as vector glyphs and bezier curves, not bitmap pixels. Compressing a PDF only optimizes image streams and font dictionaries; text stays razor-sharp and fully searchable at any zoom.
How does image downsampling (150 DPI vs 300 DPI) affect file size?▼
Images account for 80-95% of most PDF sizes. Reducing image density from 300 DPI (print standard) to 150 DPI (screen standard) cuts image data by roughly 75%, resulting in dramatically smaller PDF attachments.
Can I compress scanned PDF documents containing only images?▼
Yes! Scanned paper documents often contain massive raw TIFF or uncompressed bitmaps. Our engine applies advanced JPEG/JBIG2 compression algorithms to shrink scanned pages substantially.
Will compression remove interactive form fields, annotations, or bookmarks?▼
No. Interactive form elements, bookmarks, hyperlinks, and document outlines are carefully preserved during optimization.
Can I compress password-protected PDF files?▼
You must enter the opening password so our engine can access and optimize the document content stream. Once compressed, you can re-encrypt the file using our Protect PDF tool.
How do I compress a PDF to under 100 KB, 200 KB, or 1 MB for government/job portals?▼
Choose the 'Extreme Compression' preset. If your file is still over the limit, use our companion 'Split PDF' tool to remove unnecessary pages or downsample heavy high-resolution cover photos.
Are my private contracts and tax forms safe when using this online compressor?▼
Yes. Files are processed in secure memory buffers with 256-bit SSL encryption and deleted immediately after download. We never view, retain, or share your document data.
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